Viability Of Streptococcus Mutans Research Articles

Photoinactivation Effects of Curcumin, Nano-curcumin, and Erythrosine on Planktonic and Biofilm Cultures of Streptococcus mutans.

Introduction: This in vitro study was conducted to assess the phototoxic effects of curcumin, nano-curcumin, and erythrosine on the viability of Streptococcus mutans (S. mutans) in suspension and biofilm forms. Methods: Various concentrations of curcumin (1.5 g/L, 3 g/L), nano-curcumin (3 g/L), and erythrosine (100 μM/L, 250 μM/L) were examined for their impact on planktonic and biofilm cultures of S. mutans, either individually or in conjunction with light irradiation (photodynamic therapy or PDT). A blue light-emitting diode (LED) with a central wavelength of 450 nm served as the light source. The results were compared to 0.12% chlorhexidine digluconate (CHX) as the positive control, and a solution containing neither a photosensitizer (PS) nor a light source as the negative control group. The dependent variable was the number of viable microorganisms per experiment (CFU/mL). Results: Antimicrobial PDT caused a significant reduction in the viability of S. mutans in both planktonic and biofilm forms, compared to the negative control group (P<0.05). The highest cell killing was observed in PDT groups with curcumin 3 g/L or erythrosine 250 μmol/L, although the difference with PDT groups using curcumin 1.5 g/L or erythrosine 100 μmol/L was not significant (P>0.05). Antimicrobial treatments were more effective against planktonic S. mutans than the biofilm form. Conclusion: PDT with either curcumin 1.5 g/L or erythrosine 100 μmol/L may be suggested as an alternative to CHX to inactivate the bacteria in dental plaque or deep cavities. Nano-curcumin, at the selected concentration, exhibited lower efficacy in killing S. mutans compared to Curcumin or erythrosine.

Cytotoxicity evaluation, antibacterial effect, and degree of conversion of QAM-containing adhesives.

The aim of this study was to evaluate the influence of adding quaternary ammonium methacrylates (QAMs) to experimental adhesives by assessing the degree of conversion (DC), cytotoxicity against keratinocytes and fibroblasts, and antibacterial activity against biofilm formation. Two QAMs were added to an experimental adhesive: dimethylaminododecyl methacrylate bromododecane (DMADDM) or dimethylaminododecyl methacrylate bromohexadecane (DMAHDM) at three concentrations each: 1, 2.5, and 5 wt.%. Experimental adhesive without QAMs (control group) and commercially available Transbond XT Primer (3M Unitek, Monrovia, California, USA) were used for comparisons. The adhesives were tested for DC, cytotoxicity against keratinocytes and fibroblasts, and antibacterial activity against biofilm formation. DC, cytotoxicity against fibroblasts, and antibacterial activity were analyzed using one-way ANOVA and Tukey's multiple comparisons. Cytotoxicity against keratinocytes was evaluated using the Kruskal Wallis and Dunn's post-hoc (α = 5%) tests. Transbond showed lower DC as compared to 5% DMAHDM, 1% DMADDM, and 5% DMADDM (p < 0.05). However, all groups presented proper DC when compared to commercial adhesives in the literature. In the evaluation of cytotoxicity against keratinocytes, Transbond induced higher viability than 2.5 wt.% groups (p < 0.05). Against fibroblasts, Transbond induced higher viability as compared to 5 wt.% groups (p < 0.05). DMAHDM at 5 wt.% reduced biofilm formation when compared to all the other groups (p < 0.05). Despite their cytotoxic effect against keratinocytes, gingival fibroblasts showed higher viability. DMAHDM at 5 wt.% decreased Streptococcus mutans viability. The incorporation of DMAHDM at 5 wt.% may be a strategy for reducing the development of white spot lesions.

Morphological changes and viability of Streptococcus mutans biofilm treated with erythrosine: A confocal laser scanning microscopy analysis.

Antimicrobial photodynamic therapy (a-PDT) is a modality that aims to induce microorganisms through visible light, a photosensitizer, and molecular oxygen. This therapy has shown promising results in controlling cariogenic biofilm in vitro and in vivo counterparts. This study investigated bacterial viability and morphological characterization of Streptococcus mutans mature biofilms after combination of erythrosine and a high potency dental curing light. Biofilms were formed on saliva-coated hydroxyapatite disks in batch culture. The samples were performed in triplicates. Fresh medium was replaced daily for five days and treated using 40 μM of E activated by HL 288 J/cm2 and total dose of 226 J at 1200 mW/cm2. Phosphate buffer saline and 0.12% of chlorhexidine were used as negative and positive control, respectively. After treatment, biofilms were assessed for microbial viability and morphological characterization by means of bio-volume and thickness. COMSTAT software was used for image analysis. Data were analyzed using two-way ANOVA followed by Tukey test with significance level 5%. The application of a-PDT and CHX treatments decreased S. mutans bacterial viability. The image analysis showed more red cells on biofilms when compared to other groups, demonstrating photobacterial killing. Erythrosine irradiated with a high potency curing light can potentially act as an antimicrobial tool in the treatment of cariogenic biofilms. The morphology and viability of microorganisms were impacted after treatment. Treatment with photodynamic therapy may be able to reduce the bio-volume and viability of bacteria present in biofilms. CLINICAL RELEVANCE AND RESEARCH HIGHLIGHTS: The use of the a-PDT technique has been applied in dentistry with satisfactory results. Some applications of this technique are in stomatology and endodontics. In the present study, we sought to understand the use of photodynamic therapy in the control of biofilm and the results found are compatible with the objective of microbiological control proposed by this technique, thus raising the alert for future studies in vivo using the combination of a-PDT with erythrosine, since they are easily accessible materials for the dental surgeon and can be applied in clinical practice.

Effect of different finishing and polishing procedures on surface roughness and microbial adhesion on highly-filled composites for injectable mold technique.

To evaluate the effect of different finishing and polishing procedures on surface roughness and microbial adhesion and viability of Streptococcus mutans on novel highly-filled composites for injectable mold technique. One hundred sixty specimens were divided into four material groups: FSF (Filtek Supreme Flowable Restorative), TE (Tetric EvoFlow), GUI (G-aenial Universal Injectable) and GUF (G-aenial Universal Flo). Within each group, specimens were split regarding finishing and polishing (F/P) procedures into: SLD (Sof-Lex Discs), SLS (Sof-Lex Spirals), OG (OneGloss) and PG (PoGo). Surface roughness was analyzed using profilometer (Ra and Rz) and scanning electron microscopy (SEM) and Strep. mutans biofilm formation was analyzed using colony forming unit (CFU) and cell viability assay. Two-way analysis of variance (ANOVA) followed by Tukey's post hoc test were used for comparison among groups, Pearson's coefficient was applied for the correlation between Ra and CFU/ml and all data were presented as mean ± SD. Both materials and F/P procedures affect Ra, Rz and Strep. mutans CFU/ml values (p ≤ 0.05). Considering the Ra and Rz, GUI and GUF revealed lower values, compared to FSF and TE and SLD and SLS revealed lower values, compared to OG and PG. Considering the Strep. mutans CFU/ml and viability, GUI and TE presented lower values, compared to GUF and FSF and SLD and SLS presented lower values, compared to OG and PG. Moderate positive correlation was found between Ra and CFU/ml (r = 0.552). The smoothest surfaces possess GUI and GUF, among materials and SLD and SLS, among F/P procedures. GUI adhered the lowest amount of Strep. mutans, due to the smoothest surfaces. FSF and GUF revealed the highest amount of Strep. mutans, due to bis-GMA, bis-MEPP and TEGDMA in their composition. The findings of the present study may be beneficial for the proper selection of highly-filled composites and an adequate finishing and polishing procedure when performing the injectable mold composite resin veneer technique.

The Effect of Diode Laser on Viability and Antibiotic Sensitivity of Streptococcus mutans Isolated From Dental Caries

Streptococcus mutans is one of the major cariogenic microbial flora. In an attempt to determine the mutagenic effect of diode laser on the viability and antibiotic sensitivity of this bacteria; A total of 30 samples were collected from dental caries. The isolates were identified using by conventional identification methods and confirmed using VITEK2 system. Twenty-one isolates were recorded as Streptococcus spp and ten of them were identified as Streptococcus mutans. Antibiotic susceptibility profile for Streptococcus mutans isolates against ten antibiotics was tested. The results revealed that all the isolates were resistant to cefixime and cephalothin, nine of them were resistant to erythromycin, ampicillin, and nalidixic acid, seven isolates were resistant to tetracycline and bacitracin, whereas all isolates were sensitive to chloramphenicol, ciprofloxacin and gentamycin. The effect of the diode laser on the isolates (S5 and S10) was tested at different time intervals (1, 2, 5, and 10) min. The viability of Streptococcus mutans isolates was affected by the obvious change in the behaviour of the bacteria from resistance to sensitivity after Laser exposure

Impact of curcumin loading on the physicochemical, mechanical and antimicrobial properties of a methacrylate-based experimental dental resin

Oral biofilms are directly linked to one of the most common chronic human diseases, dental caries. Resin-based dental materials have significant potential to replace amalgam, however they lack sufficient antimicrobial power. This innovative study investigates a curcumin-loaded dental resin which can be utilized in an antimicrobial photodynamic therapy (aPDT) approach. The study evaluated the effects of curcumin loading on resin physicochemical, mechanical, and adhesive properties, as well as the antimicrobial response associated with blue light activation. Preliminary tests involving degree of conversion (DC) and sample integrity determined the optimal loading of curcumin to be restricted to 0.05 and 0.10 wt%. These optimal loadings were tested for flexural strength (FS), water sorption (WS) and solubility (SL), shear bond strength to dentin (SBS), and viability of Streptococcus mutans under 14.6 J/cm2 blue light or dark conditions, in 6 h and 24 h biofilms. The results demonstrated that 0.10 wt% curcumin had minimal impact on either FS or SBS, but detectably increased WS and SL. A 2 log10 (CFU/mL) reduction in S. mutans after light application in both 6 h and 24 h biofilms were corroborated by CLSM imaging and highlighted the significant potential of this novel aPDT approach with resin-based dental materials.

Nickel Release and the Viability of Streptococcus mutans Corresponding to Low Risk of Dental Caries in Artificial Saliva Containing Orthodontic Appliances: In Vitro Study.

The aims of this study were to determine the effect of different levels of Streptococcus mutans that correspond to a low risk of dental caries on nickel release and to determine the viability of S. mutans. Simulated fixed orthodontic appliances composed of copper nickel titanium, nickel titanium, or stainless steel were immersed in Klimek artificial saliva for 10 days with or without S. mutans inoculation on day 7. Same levels of S. mutans cultures (4 × 104 cfu/mL) were inoculated into the artificial saliva without orthodontic appliances. Nickel release was detected by inductively coupled plasma mass spectrometry. The archwire surface was analyzed by atomic force microscopy and scanning electron microscopy. The density of S. mutans significantly increased in the artificial saliva without orthodontic appliances (P < .05). Appliances with nickel titanium alloys showed higher nickel release in the artificial saliva with or without S. mutans than those with copper nickel titanium or stainless steel archwires (P < .05). However, S. mutans increased nickel release only in orthodontic appliances with stainless steel archwires (P < .05). Although atomic force microscopy showed that the surface of as-received stainless steel archwires was smoother than that of nickel titanium or nickel titanium archwires, S. mutans increased the surface roughness of only the SS archwires. S. mutans adhered to all archwire types. While corrosion or corrosion-related processes may have decreased the growth capacity of S. mutans, reciprocally, S. mutans influenced corrosion. Rough surfaces can also promote corrosion; therefore, the surface roughness of metal alloy orthodontic appliances should be evaluated to determine their corrosion behavior.

Exploring the Physicochemical, Mechanical, and Photocatalytic Antibacterial Properties of a Methacrylate-Based Dental Material Loaded with ZnO Nanoparticles.

While resin-based materials meet the many requirements of a restorative material, they lack adequate, long-lasting antimicrobial power. This study investigated a zinc oxide nanoparticle (ZnO NP)-loaded resin-blend (RB) toward a new antimicrobial photodynamic therapy (aPDT)-based approach for managing dental caries. The results confirmed that up to 20 wt% ZnO NPs could be added without compromising the degree of conversion (DC) of the original blend. The DC achieved for the 20 wt% ZnO NP blend has been the highest reported. The effects on flexural strength (FS), shear bond strength to dentin (SBS), water sorption (WS), solubility (SL), and viability of Streptococcus mutans under 1.35 J/cm2 blue light or dark conditions were limited to ≤20 wt% ZnO NP loading. The addition of up to 20 wt% ZnO NPs had a minimal impact on FS or SBS, while a reduction in the bacteria count was observed. The maximum loading resulted in an increase in SL. Furthermore, 28-day aging in 37 °C water increased the FS for all groups, while it sustained the reduction in bacteria count for the 20 wt% resin blends. Overall, the ZnO NP-loaded resin-based restorative material presents significant potential for use in aPDT.

Photodynamic potential of curcumin in bioadhesive formulations: Optical characteristics and antimicrobial effect against biofilms

Background: Although Curcumin (CUR) has great potential as a photosensitizer, the low solubility in water impairs its clinical performance in photodynamic inactivation (PDI). This study sought to establish an effective antimicrobial protocol for PDI using CUR in three different bioadhesive formulations. Methods: A CUR-loaded chitosan hydrogel with a poloxamer (CUR-CHIH), a CUR-loaded liquid crystal precursor system (CUR-LCP), a CUR-loaded microemulsion (CUR-ME), and CUR in dimethylsulfoxide (DMSO) solution (CUR-S; control formulation) were tested against in vitro and in situ oral biofilms. The optical properties of each formulation were evaluated. Results: All of the formulations exhibited lower absorbance than CUR-S; however, the CUR-LCP curve bore the highest resemblance. The CUR present in all formulations was completely degraded after 15 min of illumination. In vitro experiments showed that CUR-S was the only formulation able to significantly reduce biofilm viability of Candida albicans and Lactobacillus casei when compared to the negative control (no PDI); the amount of reduction obtained was 1.8 and 3.7 log (CFU/mL) for C. albicans and L. casei, respectively. There was a significant reduction on the viability of Streptococcus mutans biofilms when CUR-S and CUR-LCP were applied (approximately 3.5 and 1.6 log [CFU/mL], respectively). In situ testing showed antimicrobial efficacy against S. mutans and general microorganisms. Conclusions: Although the evaluated protocols has not been effective to all of the evaluated microorganisms, PDI showed potential against dental biofilms and evidence that the phototoxic effects of CUR have a high relation with the type of formulation in which it is loaded.

Influence of Additive Firing on the Surface Characteristics, Streptococcus mutans Viability and Optical Properties of Zirconia.

The purpose of this study was to observe whether the repetitive firing of dental zirconia caused changes in surface characteristics, S. mutans viability, and optical properties of zirconia. Dental zirconia blocks were sintered and randomly distributed into seven experimental groups: F0–F6. Except for F0, which only went through sintering, the additive firing was performed in order for F1–F6. Surface roughness, contact angle, S. mutans viability by fluorescence, and translucency parameter were measured. They were all highest after sintering (F0) and decreased after additive firings (F1–F6). The additive firing of zirconia after sintering decreased surface roughness, contact angle, S. mutans viability, and translucency. The number of firings after the first firing was not found to be critical in surface characteristics, S. mutans viability, and optical property. Changes in surface characteristics might have led to a decrease in S. mutans viability, while the change of translucency was not clinically significant. This implies that additive firing may prevent secondary caries under zirconia restorations, not compromising esthetic appearance.

Nanometric Deposition of Fluoride Ions on Titanium Alloys and its Influence on In Vitro Bacterial Adhesion and Viability

Bacterial colonization plays a key role on the pathogenesis of peri-implantitis and may be influenced by titanium surface topography. The aim of this in vitro study was to evaluate the influence of titanium topography after fluoride ions deposition in the bacterial colonization. Machined (M), double acid-etched (DE) and double acid-etched surface with fluoride ions deposition (Nano F-) were analyzed by scanning electron microscopy, contact angle and roughness (Ra). Streptococcus mutans viability was quantified by Live/Dead Baclight bacterial viability kit. The mean Ra/contact angle values were 0.20 μm/69.13°, 0.53 μm /92.82° and 0.56 μm/94.33° for M, DE and Nano F-, respectively. M surface presented significantly lower live bacterial counts when compared to the Nano F- surface (p=0.007). The dead bacteria count was higher on the Nano F- surface (p=0.001) than on the M and DE surfaces. Crystalline deposition of fluoride ions (Nano F-) promoted an increase in dead bacteria on the tested titanium surface.

Surface Modification by Nano-Structures Reduces Viable Bacterial Biofilm in Aerobic and Anaerobic Environments.

Bacterial biofilm formation on wet surfaces represents a significant problem in medicine and environmental sciences. One of the strategies to prevent or eliminate surface adhesion of organisms is surface modification and coating. However, the current coating technologies possess several drawbacks, including limited durability, low biocompatibility and high cost. Here, we present a simple antibacterial modification of titanium, mica and glass surfaces using self-assembling nano-structures. We have designed two different nano-structure coatings composed of fluorinated phenylalanine via the drop-cast coating technique. We investigated and characterized the modified surfaces by scanning electron microscopy, X-ray diffraction and wettability analyses. Exploiting the antimicrobial property of the nano-structures, we successfully hindered the viability of Streptococcus mutans and Enterococcus faecalis on the coated surfaces in both aerobic and anaerobic conditions. Notably, we found lower bacteria adherence to the coated surfaces and a reduction of 86–99% in the total metabolic activity of the bacteria. Our results emphasize the interplay between self-assembly and antimicrobial activity of small self-assembling molecules, thus highlighting a new approach of biofilm control for implementation in biomedicine and other fields.

Effect of Nano Hydroxyapatite in Toothpaste on Controlling Oral Microbial Viability

The aim of this study is to examine the effect of nano hydroxyapatite in the toothpaste and its effect on the pH and microbial activity. Nano-hydroxyapatite (nHAp) is considered one of the materials that have high biocompatibility for biomimetic material due to its chemical and morphological similarity with dental apatite. Additionally, it has been documented to possess antibacterial potentials. The present study was conducted to identify the relationship between oral microenvironment pH change and its role in the Streptococcus mutans viability, a common pathogen in the oral cavity. Change in pH is closely related to number of Streptococcus mutans as the main cariogenic organism and acid-producing bacteria. The study was carried out using 0.25%, 0.7%, and 1.5% concentration of HAp in toothpaste formulation and commercial toothpaste as control. Our studies showed that the most significant pH fall was observed in 1.5% and 0.7% nHAp. However, in 60 minutes, all nHAp groups were able to restore pH into neutral, especially in the 0.7% nHAp, which reached a pH of 7. As a comparison, the commercial toothpaste only returned to 6 within 1 hour. Experimental method of this study is In vitro oral microenvironment pH and microbiological analysis on teeth fragment. The detailed data about microstructure and antibacterial activity will be presented.

Growth and viability of Streptococcus mutans in sucrose with different concentrations of Stevia rebaudiana Bertoni.

To evaluate total absorbance, planktonic growth, biofilm formation, viability, metabolic activity, and pH of Streptococcus mutans UA159 cultures when different dilutions of Stevia rebaudiana Bertoni were applied and to determine the minimum inhibitory concentration (MIC) and the minimum biofilm inhibitory concentration (MBIC) of Stevia on S. mutans. The effects of different dilutions of Stevia (0-400mg/ml) on S. mutans total growth, planktonic growth, biofilm formation, viability, metabolic activity, and pH during a 72-h growth period were evaluated in this in vitro study. A stock solution was prepared by mixing 10ml of tryptic soy broth (TSB) supplemented with 1% sucrose (TSBS) and 4g of Stevia. S. mutans total growth and biofilm formation decreased with reduced concentrations of Stevia. Furthermore, the MIC was 25mg/ml and the MBIC was 6.25mg/ml. Complete eradication of S. mutans was not observed with any of the Stevia concentrations. Planktonic growth of S. mutans was not repressed by high concentrations of Stevia and most of the Stevia concentrations generated an increased pH. Because Stevia reduces biofilm and acid production, Stevia can be considered a non-cariogenic sweetener. This study confirms the anticariogenic effect of Stevia, like it has been previously reported, but more studies on the most effective concentration are needed, and in the present study, the minimum inhibitory concentration (MIC) and the minimum biofilm inhibitory concentration (MBIC) was determined in the presence of sucrose. Additionally, this is the first study to evaluate the effect of Stevia on S. mutans metabolic activity.

Chemical, Mechanical and Biological Properties of an Adhesive Resin with Alkyl Trimethyl Ammonium Bromide-loaded Halloysite Nanotubes.

The aim of this study was to evaluate the chemomechanical properties, antibacterial activity, and cytotoxicity of an experimental adhesive resin containing halloysite nanotubes (HNT), doped with alkyl trimethyl ammonium bromide (ATAB). A filler of HNT doped with ATAB was obtained (ATAB:HNT) and incorporated (5 wt%) into a resin blend made of bisphenol A glycerolate dimethacrylate, 2-hydroxyethyl methacrylate and a photoinitiator/co-initiator system (GATAB:HNT). The same resin blend without ATAB:HNT was used as control (Ctrl). The ATAB:HNT filler was assessed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The two tested adhesives were evaluated for degree of conversion (DC) in vitro and in situ, softening in alcohol, dentin microtensile bond strength (µTBS), antibacterial activity, and cytotoxicity (n = 5). SEM showed that the nanotubes had a characteristic tubular-needle morphology, while the TEM analysis confirmed the presence of ATAB inside the lumens of HNT. The incorporation of ATAB:HNT induced no reduction (p > 0.05) of the DC either in situ or in vitro. No difference was encountered after the softening challenge test (p > 0.05) and no difference was found in µTBS between the two adhesives, both at 24 h (p > 0.05) and after 6 months of storage in distilled water (p > 0.05). However, ATAB:HNT reduced Streptococcus mutans viability (p < 0.05) without a cytotoxic effect on pulp cells (p > 0.05). GATAB:HNT adhesive demonstrated appropriate polymerization without significant differences in softening after solvent immersion, while concomitantly maintaining reliable bond strength after 6 months of water aging. Moreover, the ATAB:HNT filler can provide antibacterial activity to the adhesive resin without affecting pulp cell viability.

Effect of curcumin-mediated photodynamic therapy on Streptococcus mutans and Candida albicans: A systematic review of in vitro studies.

There is still no systematized evidence in the literature regarding the combination of curcumin to improve the effects of antimicrobial photodynamic therapy (aPDT) on complex oral biofilms. Therefore, the objective of this review was to systematically assess the antimicrobial effect of curcumin-mediated aPDT on the vitality of biofilms of microorganisms Streptococcus mutans and Candida albicans. The addressed focused question was: "What are the effects of curcumin-mediated antimicrobial therapy on the biofilm viability of Streptococcus mutans and Candida albicans in vitro models?" A literature search was conducted in the electronic databases Pubmed, Web of Science, Scopus, Cochrane Library and Bireme up to April 2019. In vitro studies evaluating the effect of curcumin-mediated antimicrobial photodynamic therapy on S. mutans and C. albicans biofilms were included. From 95 citations, 11 full-text articles were screened and 6 studies were included in this review. Because of the heterogeneity observed in the studies selected, meta-analysis was not possible. The in vitro studies indicate the potential use of curcumin-mediated aPDT to inactivate microorganisms; Streptococcus mutans and Candida albicans. This survey should be viewed as a starting point for further examinations using standardized parameters to enhance outcomes.

In Vitro Evaluation of Bacterial Adhesion and Bacterial Viability of Streptococcus mutans, Streptococcus sanguinis, and Porphyromonas gingivalis on the Abutment Surface of Titanium and Zirconium Dental Implants.

Objective To evaluate the in vitro adherence and viability of 3 bacterial species Streptococcus mutans (ATCC 25175), Streptococcus sanguinis (ATCC 10556), and Porphyromonas gingivalis (ATCC 33277) on the surfaces of dental implants of titanium, zirconium, and their respective fixing screws. Methods Two analysis groups were formed: group 1 with 3 titanium pillars and group 2 with 3 zirconium pillars, each with their respective fixing screws. Each of these groups was included in tubes with bacterial cultures of Streptococcus mutans (ATCC 25175), Streptococcus sanguinis (ATCC 10556), and Porphyromonas gingivalis (ATCC 33277). These samples were incubated at 37°C under anaerobic conditions. Bacterial adherence was assessed by measurement of the change in colony-forming units (CFU), and bacterial viability was evaluated with the colorimetric test of 3-(4,5-dimethylthiazol-2)-2,5 diphenyl tetrazolium bromide (MTT). Results The bacterial adhesion in the titanium abutments was higher for Streptococcus mutans (190.90 CFU/mL), and the viability was greater in Porphyromonas gingivalis (73.22%). The zirconium abutment group showed the highest adherence with Streptococcus mutans (331.82 CFU/mL) and the highest bacterial viability with the S. sanguinis strain (38.42%). The titanium fixation screws showed the highest adhesion with S. sanguinis (132.5 CFU/mL) compared to the zirconium fixation screws where S. mutans had the highest adhesion (145.5 CFU/mL). The bacterial viability of S. mutans was greater both in the titanium fixation screws and in the zirconium fixation screws 78.04% and 57.38%, respectively. Conclusions Our results indicate that there is in vitro bacterial adherence and viability in both titanium abutments and zirconium abutments and fixation screws for both. Streptococcus mutans is the microorganism that shows the greatest adherence to the surfaces of both titanium and zirconium and the fixing screws of the latter. On the contrary, bacterial viability is greater on the titanium abutments with P. gingivalis than on the zirconium abutments with S. sanguinis. With respect to the fixation screws, in both cases, the viability of S. mutans was greater with respect to the other bacteria. In general, the titanium abutments showed less adherence but greater bacterial viability.

Estimation of salivary pH and viability of Streptococcus mutans on chewing of Tulsi leaves in children.

The current concepts of dental caries focus on cariogenic bacteria such as Streptococcus mutans fermenting carbohydrates to form organic acids, which cause a drop in pH, resulting in demineralization of the tooth surface.[l] Studies show that Tulsi has broad-spectrum antimicrobial activity.[2] Hence, this study aimed at estimating the change in salivary pH and viability of S. mutans on chewing of Tulsi leaves, in children. This study aimed to estimate the change in salivary pH and viability of S. mutans on chewing of Tulsi leaves. The study was carried out on thirty children aged 9-12 years. Oral prophylaxis was performed prior to sample collection. Three samples were collected per child, one before and two after chewing of Tulsi leaves. The change in salivary pH and viability of S. mutans was assessed. The obtained data were analyzed using Friedman test and Wilcoxon's test. The level of significance was set at P < 0.05. The results obtained showed no significant difference in the pH values obtained from the samples, but there was a significant difference in the S. mutans' colony counts. Based on the results obtained from this study, it may be concluded that Tulsi (Ocimum sanctum) has the potential to be developed into an antimicrobial agent against cariogenic bacteria, specifically S. mutans.

Antimicrobial activity of Cymbopogon citratus (Poaceae) essential oil on Streptococcus mutans biofilm and cytotoxic effect on keratinocytes and fibroblasts

Dental caries is a pathology of multifactorial origin and currently natural products are an efficient alternative treatment; The work sought to evaluate the antimicrobial activity of the Cymbopogon citratus essential oil and the citral and myrcene components against Streptococcus mutans ATCC UA159, as well as their cytotoxicity on keratinocytes and human fibroblasts. The viability effect against Streptococcus mutans on biofilms was evaluated through exposure to the three substances by using the MBEC technique-high-throughput at concentrations of 1, 0.1, and 0.01 µg/mL and chlorhexidine as positive control. The cytotoxicity of the compounds was evaluated on keratinocytes and fibroblasts through the MTT reduction technique, using 0.5 mM H2O2 as cell-death control (negative control) and ethanol 1% as vehicle control (positive control). The three substances evaluated had effects on the viability of Streptococcus mutans with mortality between 74% and 96%, without significant difference among them (p &gt; 0.393); additionally, no cytotoxicity was evident on keratinocytes and fibroblasts in a 24-h treatment. The substances evaluated showed significant antimicrobial effects; hence, these should be studied further as potential co-adjuvants to prevent dental caries that cause minor adverse effects

Effect of storage temperature on Streptococcus mutans viability

Abstract Introduction Proper storage conditions and maintenance of viable biological material plays an important role in microbiological research, allowing for the opportunity to conduct future studies. Objective To evaluate the viability of Streptococcus mutans strains that were previously grown and stored under different temperatures for approximately eight years. Material and method In this study, we evaluated 393 bacterial isolates that were stored in a freezer at -80°C (G1) and 200 isolates stored in a freezer at -20°C (G2). Aliquots of each sample were plated on blood agar and mitis-salivarius bacitracin sucrose agar-solidified medium. After incubating under microaerophilic conditions in an incubator at 37°C for 72 hours, the presence, morphology and purity of bacterial growth was observed. The data were analyzed by means of descriptive statistics. Result Microbial viability was observed in almost all samples (99.7%) in G1, whereas all isolates stored at -20°C were considered inviable. Conclusion The viability of S. mutans is influenced by the storage temperature of the samples, and the strains remain viable when stored under ideal temperature conditions (-80°C), even when stored for a long period of time.